Swap
by Kitt SummerIsle
Summary: It was probably Wheeljack's fault. It was usually Wheeljack. But knowing the culprit helped very little Optimus. He longed to be back on his wheels. Now. Before Megatron ruined them all.
1. Chapter 1

I.

Optimus lurched sideways, nearly falling to his knees as the wave of dizziness hit. There was a wall to one side and he grabbed it to steady his queasily roiling frame. His helm felt so heavy he wanted nothing more than put it down and recharge until Ratchet could fix whatever was wrong with it… and him. Too bad they were in the midst of the battle and Megatron could exploit his sudden dizziness with a blow at any klik, so Optimus tried to collect himself and stand up straight. He stared at the wall that crumbled in his grip, a concrete beam bending like it was cheap plastic, the dust of the cement covering his servo and making his vents sputter in irritated indignation. He couldn't remember being able to break reinforced concrete just like that. And why was his helm so… heavy and restricting… and why couldn't he see properly?

Optimus turned that too-heavy, unwieldy helm from side to side to see whether Megatron was following up his earlier attack but his optics were not cooperating with him. It was far too early in the battle for the warlord to call a retreat so he must be somewhere around. He tried to shake his helm in hopes of clearing his strangely uncooperative processor, but the movement felt like an exercise in futility with how heavy it was, how big, how the open air… what? Optimus wasn't used to feeling air on his faceplates, he was using his mask nearly all the time these vorns and certainly never opening it in a battle! But he couldn't find the protocols to close it, they have somehow disappeared along with the safety of the plate. But there was no pain telling him that it was torn or removed, nothing. Like it never existed.

 _I must have received a stronger blow than I remember…_

Optimus collected fleeing thoughts and reordered the chaotic threads in his meta. Pedes felt heavy and enlarged for some reason, in fact his whole leg assembly was at least twice the weight he was used to. Helm too as he had already realized. Right arm, the one grabbing the crumbling wall… not only heavy, but registering nearly thrice of the diameter he remembered and cumbersome like it didn't even belong to him, like it was a useless, heavy, thrumming and smoldering hot _something_ he could hardly lift, much less swing if Megatron decided it was high time to attack and decide their fight.

Which, come to think of it was surprisingly late to come. Optimus felt like he was dizzily standing there leaning heavily onto the wall and trying to collect his errant wits for breems – certainly more time than Megatron usually took to exploit his perceived weaknesses. So why was a hit not coming while he couldn't counter it? The standard noise of the battle filtered into his audials like they were coming through a layer of cotton, though why would he or anymech else would smother his audials in organic material he would never know, but that was how humans described a sensation to him once and the expression felt strangely but aptly fitting now.

The world still wavered a bit but started to clear up slowly, like fog dissipating from the air and Optimus felt more steady on those still-too-heavy and still-too-big pedes. Optics tried to focus, the delicate mechanisms moving the lenses in and out, rotating the leafs of the shutter in a heroic effort to see. Megatron's silver plating was nowhere to be seen and he ex-vented a tiny sigh of relief, lifting a servo to his helm to try and find the errant mask he keenly missed… and he promptly yelled out as the unexpectedly big _something_ clanged into his helm, only it came out more like a howl at the sudden pain of a dent and Optimus suddenly didn't know which shocked him more, the sound he produced or the hit he dealt to himself.

 _I don't even need Megatron to knock myself out…?_

But why was he so clumsy all of a sudden? Or rather… why was his arm so big? Optimus lifted the arm again, slower this time with more care and stared at it incomprehensively. It just… made no sense whatsoever. None at all to have Megatron's cannon on it. At least he knew now why he clanged it into his helm. But his subprocessor insisted that it wasn't somemech else's cannon, it was HIS. It unhelpfully loaded the targeting system too to prove it. It overlaid his HUD and started to label mechs around him with targeting ratios, percentages of probable damage, evaluation of threats… and why was there a separate subroutine that had no other job but track Starscream as a particularly dangerous target?

The uncomfortable – and heavy – truth started to settle in his processor. All the anomalies, all the differences, the strangeness… and the cannon sealed it, proved it in a way hardly anything else could. Optimus looked down with clear optics now, noting the reddish tint of his own gaze, but dismissing it for more important matters… yes, his frame was grey and black, silvery and stark metal, pitted and scratched and much thicker than his own; heavy, safe plates of a gladiator-armour, unlike his reinforced civilian one, the large, strong pieces interconnected and overlapped for maximum protection, the powerful power-plant idling beneath comfortably but perfectly able to power strong and thick-plated limbs for devastating blows… as he well knew from the receiving end.

 _So… I am in Megatron's frame. How curious._

But he had no time for shock and if he was in the warlord's frame, then where was his? The helm was starting to bother Optimus. It was not only incredibly heavy and unwieldy, but very restrictive too, he could barely see to the sides, his audials still felt like muffled, even though he did hear the battlefield noises perfectly well and the targeting software appeared to have a processor of its own, requiring him to emphatically _deny_ firing the cannon every few kliks or so. Still, he tried to swing the heavy helm left and right, scanning the chaotic battlefield that not only had a lot of smoke and dust to make visibility nearly zero, but also it was overlaid by a tactical layer similar to his own, but the complexity of it shocked Optimus greatly. It was obviously a close-quarter fighting one – no wonder Megatron preferred to wade into a battle instead of orchestrating it from the back lines – and it had incredibly details and threat analysis of every mech near enough to be considered one. And it suddenly zeroed in on a particular frame, not far from him, lighting up in purple like a mad fireworks display…

 _Oh, for Primus's sake…_

Optimus ground sharp dentae he was afraid to label as fangs, growled, shocked himself with the sound but managed to shut down his cannon completely, forcing his will over insistent software and energon-thirsty protocols. He did not want to accidentally shoot his own frame which the cannon all-too eagerly wanted to do. He had never known Megatron acted so much on preprogrammed impulses and set protocols. No wonder the mech appeared to never listen to reason – by the time arguments arrived to his processor he would have already attacked. His frame – Optimus's frame! - appeared to be even more shaky and hesitant than himself – if his guess was right and Megatron was in it, he appeared to have even more trouble adjusting to it than Optimus.

 _Let's not talk about poetic justice…_

His processor by this time felt clear enough so Optimus could forcefully shut down most of the irritating tactical display and have a real look around the battlefield. He was dismayed enough to realize that the whole exchange and adjustment took no more than two kliks and nomech else on the battlefield appeared to have noted the change. Most mechs were still fighting their own battles as per the usual choreography. That meant he might get hit by any of his own overenthusiastic Autobots trying to 'save' him… umm, his frame which now probably contained Megatron. He did rather look like standing over a fallen enemy victoriously, his dizziness and shock probably not showing outwardly.

 _I should do something about it…_

But he still didn't feel all that comfortable in the warlord's too-big, too-strong, too-eager frame to do much. Coordinated movement was a guess at best, judging from the way he nearly knocked himself out just a klik ago. Optimus quickly dropped the remains of the reinforced concrete beam from his servo sheepishly, hoping that nomech noticed him hitting himself in the helm with it, and thought furiously, trying to find a way out of this predicament. Comms! The brilliant idea came suddenly and he automatically opened a channel to his Second.

"Lord Megatron?"

 _Umm, no, no, no, not that one._

Optimus shut down the channel hurriedly with the emotionless tone of Soundwave and tried to consciously remember the Autobot frequencies. It sometimes helped to have a paranoid security director, as he forced them to change codes every decaorn and learn them by spark… yes! He remembered the correct one.

"Prowl?"

"…"

He would have to record somehow how a thoroughly shocked silence sounded from the Praxian. It wasn't all that often he was left speechless, but apparently the enemy's commander contacting him in the midst of the battle was enough.

"It's me, Prowl, Optimus Prime. I… we… appear to have exchanged frames with… umm, Megatron."

"…"

 _I hope he didn't glitch._

Optimus turned, turned back again and found the black and white frame where he remembered him to be – the opposite side of the battlefield of course, he himself was where Megatron used to stand, so facing his Autobots, have to remember that – and waved a friendly servo in the air – the one without the cannon, the one he felt he could lift comfortably and not hit himself in the helm again, and hopefully meaning less threat than the outrageously be-cannon-ed one.

"Lord… Optimus Prime? What?"

"Now, Prowl, no need to Lord me." – _for Primus's sake, where did that wretched bit of humor come from right now and why?_ – "I mean, it is really me in his… Megatron's frame. Somehow."

"Sir…" – Prowl straightened up and Optimus's targeting software nearly crowed in glee, finding another so important target and Optimus gnashed his denta in an effort to shunt it back down in the Pit. He so didn't need this! – "Please, Sir, call a ceasefire… if it is really you?"

 _Yes, that is a good idea._

But Optimus suddenly had other problems than convincing Prowl. His tactical display roared at him to FIGHTFIGHTFIGHT as Optimus, umm, his own frame with Megatron probably in it stood up, still tottering on unsteady legs and holding his helm in his servos - and his frame was moving under its own initiative and Optimus was horrified to see a silvery arm swinging around for a hit that would surely take out himself – with Megatron and all – and it was becoming extremely confusing for a klik, dizziness again swamping him as his main processor and his tactical subprocessor got into an argument about who was who, who was the enemy and was it not a god idea to shut down Megatron even if it meant damage to his own frame?

 _He might have the same conflict, causing him to be dizzy still._

The arm's arc completed, his blow connected to the blue helm and Optimus felt a pang of something indescribable as his… Megatron's… the blue helm snapped to the side – there was something for thick and heavy helms, Optimus conceded sullenly, he would never change his own headwear, but the blow knocked him… his frame out all too easily and Megatron fell back to the ground in a heap.

 _Damn._

"Cease hostilities NOW!"

Well, that might not have been the way Megatron would have expressed the order, judging from the Decepticon helms that swung towards him surprised, but at least they obeyed the order at once. There was something for tyrannical warlords too who didn't allow questioning their words. Optimus saw Prowl stand up fully and noted the rising brow of surprise mixed with worry for what he still saw as his leader downed. Ratchet and the twins guarding him were already moving towards them, unafraid for the threat he represented, the medic's single-minded focus on his damaged leader, the twins' on their medic, daring anymech to pose a threat to him. Even if Prowl decided to tell them what happened, they shouldn't believe him – and Optimus – so fast.

They didn't. Approaching with drawn weapons and suspicious glances they got closer and closer to their strange duo. But then of course things just got even more complicated than that… Optimus nearly cursed when his tactical display once again went haywire and screamed flashing purple alerts at him. Since the Decepticons were still just standing around uncomprehending Optimus at first didn't get it…

… then the slender, tricoloured frame swooping down by him explained it adequately.

"Starscream."

He wasn't even surprised to find the cannon turning itself on again and being trained on the approaching Seeker. The tactical display marked him as just slightly less of a threat than the Prime – himself. Optimus debated himself a bit whether to take that as an insult, but in the end considered it ludicrous. Who was he to judge the level and seriousness of Decepticon infighting?

"Mighty Megatron… might I enquire why did we stop the battle?"

Uhh-ohh… the Seeker seemed to be furious under the honeyed tones of his question. Optimus was surprised just how easily he read that out of the angle of those wings. His servos twitched in an unidentified motion. Unfortunately he noticed Soundwave getting closer too and his emotionless mask was disapproving as well. It might be that his unintended subterfuge was coming to an end… or it should be, really. Optimus wasn't sure he could convincingly play the warlord's part long term or if he even wanted to. With two suspicious lieutenants? Forget it.

"Everymech stop! Back!"

This time Optimus was glad to have an eagerly humming fusion cannon to back up his order.

"Starscream!"

He swung the business end with its smoldering pink energies towards the sneakily approaching Seeker and started to agree with the tactical display's assessment of him. The jet was sneaky and dangerous.

"Stand down! Prowl! A ceasefire while we discuss this?"

Prowl stood a cautious distance from him, but nodded, despite of the loudly rising disagreements from the rest of the Autobots. The situation was clearly sliding out of control – and sanity.

Optimus have had enough.

"Enough! I am Optimus Prime and that is Megatron in my frame there. Something exchanged us and I intend to fix it soonest!"

He kept an optic on Starscream and sure enough he caught the interested-eager-calculating glint in it at the declaration. The rest of the Autobots and Decepticons reacted with the expected mixture of disbelief and doubt, leaning to demands for proof from the braver mechs. A tiny, barely there touch in his processor told him that Soundwave preferred to gain first-servo evidence instead of useless questions. Optimus tightened his mental defences, but let the telepath touch the surface and gain his proof. When the masked helm nodded, many Cons fell silent. What took the telepath to be convinced was enough for many and for this Optimus felt a bit relieved. His Autobots might take a bit more to persuade of his authenticity, what with himself being in Megatron's feared frame, but Prowl seemed to accept his word and it too helped.

"Ceasefire: suggested. Exchange back: necessary. Research: needed."

Prowl nodded to Soundwave but his optics sought out Optimus's own frame, still lying on the ground. Optimus hoped that he didn't damage himself too much with that hit. It was necessary at the time – considering Megatron's usual temperament and his neglecting of any shreds of common sense in simple situations – but it was a problem now. He was compromised too, to say at least. He should entrust the negotiations to Prowl and Soundwave.

"I suggest our science team for the task. I offer safe passage for… Lord Megatron… in any frame until we can reverse the effect."

But that had the uncomfortable complication of Starscream being… well, Starscream. The Decepticon SIC.

"What? No! You won't take him as hostage!"

It was clear that Starscream himself wasn't sure which Megatron he was talking about. The frame with its threatening fusion cannon? Or the still unknown of the real Megatron is the Prime's frame? He only knew that if anymech messed with Megatron he would want to see it. Or do it himself.

"We are both hostages in each other's frame, Starscream. I wouldn't harm myself and I would hope Megatron wouldn't either. So unless you have a solution…"

"I want to be there!"

Of course… Optimus remembered that the Seeker used to be a scientist before becoming a backstabbing SIC in the Decepticon army. Well… he could keep a few optics on the Seeker to not to do any funny business. It pleased his tactical subrutines to no end.

 _What an orn…!_

"Decepticons: retreat."

Optimus opened his mouth to echo the sentiment but Prowl was faster ordering it – and thereby politely reminding his leader that while in Megatron's frame he shouldn't give orders to the Autobots.

 _Well. Better remember that._

The Decepticons transformed and flew away uneasily after Soundwave, leaving the Autobots, and the slyly smirking Starscream who apparently started to enjoy the situation, standing around. Ratchet knelt by Optimus's frame to check his vital signs and pronounced him to be fine, just temporarily out. Optimus sighed an exvent of relief. The situation was still tense but tempers started to calm down and mechs folded down to their alt-modes to get back to the Ark, uneasily avoiding the silver frame in the middle. Optimus, too initiated his transformation sequence, intending to drive after them while Ratchet took his frame back to the Ark.

The ensuing sensation was… incredible, to put it mildly. The world suddenly exploded and compressed-contorted at the same time making him groan at the wildly incomprehensible sensory input. Starscream, standing not far from him became a giant in the space of a nanoklik, while the ground jumped up to him and hit him hard in the back. Then, before he could utter a sound in shock he lost a good two third of his senses, most of his mass and all of his ability to move.

 _WHAT IN PRIMUS'S NAME…?_

Hearing was what remained most to him, though even more muffled, cottony than before. It brought to him… giggling? Chuckling, guffaws and outright, loud, incomprehensible laughter? Optimus started to freak out. What happened? Has he been exchanged back to his frame? Has Starscream done something to immobilize him? Why were mechs laughing then? Then his now incredibly narrow but sharp tunnel vision found Ratchet and the medic too was… smirking?

"What happened?"

He felt more than saw Starscream's steps come closer and squat down beside him, the scratchy voice vastly amused.

"Now I believe you being Optimus. No way _Mighty Megatron_ would forget his… alt-mode…"

Optimus wanted to facepalm, a motion of course denied to him in this form. Of course… Megatron's alt was a weapon, not a vehicle. His alt now. He considered shooting the Seeker with it between those infuriatingly amused optics. No. That was Megatron's instinct, not his. Still, the remarks and the smirks smarted his pride. He was about to transform back when he felt himself being picked up – and Optimus decided that he definitely did not like it and couldn't imagine how Megatron could stand the action. Who was it?

"So that's the Slagmaker himself… umm, sorry, Optimus, I didn't mean it that way!"

"Ironhide." – Optimus commed him in a tight voice because apparently his vocalizer was stuck in this form as well – "Put. Me. Down."

Starscream's laughter still irked him as he transformed back to stand on two, rather shaky legs again. The world imploded and distorted again, the weight returned to his frame with a vengeance and made his trembling knee-joints buckle and Optimus scowled in displeasure. The half-hidden smirks did not help. His own frame, standing now with a rather groggy Megatron in it and Ratchet's help did a little. He gave a longing little wish for his truck form. How was he supposed to move now? Walk to the Ark?

Half a breem of exciting and lively explanations later, after convincing Megatron to cooperate – as if it wasn't his goal too to return into his frame! - Optimus was lying in that accursedly helpless alt mode again, in his own truck's cabin, which was definitely a first for him, but he couldn't learn to fly that fast. Megatron was shaking in disgust on his tires and his unending angry tirade about the inherent inferiority of the frame he was forced to exist in definitely bored Optimus who couldn't answer anyhow. Starscream was cackling to himself and nearly choking with glee and not helping either manners and tempers. Which was probably why the damn Seeker insisted on staying.

And that was before they realized that Megatron couldn't drive.


	2. Chapter 2

"And just where in the slaggin' Pit could I have learned to?"

Megatron enquired at the top of his – Optimus's! - voice then followed it up with a scathing remark about the puny vocalizer's range and pitch and yanked the wheel to the left again, with his, by this time usual crudeness and ferocity. The wheel gave a pitiful groan, which Optimus silently echoed, the big truck's wheels squealed on the road and bumped back up the tarmac, leaving a plume of dust as contrail behind them from the hard shoulder. The Autobots wisely kept a considerable distance around them, partly for diverting unsuspecting human traffic, partly because even Jazz with his lightning-quick reflexes was afraid to come closer to the erratically lurching huge red and blue truck that seemingly found even the four-lane highway too constraining. The quick crash course of the controls before they could start the way home apparently helped very little to Megatron's ability to actually drive a truck.

"I thought you had a different alt mode before the war. Umm. Ack." – Optimus slid across the seat and bumped into the backrest as the truck suddenly and for no reason braked and lurched ahead jarringly again. He felt sorry for his poor, abused brakes too and wondered why the gaspedal was so… jerky? – "I mean you couldn't have had a gun alt as a miner, right?"

He desperately wished he had a servo in this accursed gun mode. Or a tentacle. Something to keep him from unintentionally visiting parts of his own cabin he never had the opportunity before. The seat-belt was a joke. Then they stopped and Ratchet wedged him into the edge between the seat and the backrest and Optimus didn't have the spark to ask him whether he remembered what part of _his_ anatomy that was. Surely the medic knew. Worse, Megatron also had to know it by now, though he thankfully never mentioned it in his angry tirades. Nevertheless, Optimus was actually kind of glad when Megatron swerved off the road completely, into the shallow ditch, blew a tire and the resulting bump dislodged him from the undignified position. But his suspension was not designed to fly even for a few meters and Optimus's spark ached as he heard the tortured noise erupting from it when they touched down. He thought he had heard the Seeker's cackling laugh from above, but it must have been his imagination. He couldn't have flown so low to see it, right?

"Miners didn't have alt modes, slag you and your high-and-mighty kind!"

Since then it was bump after bump, lurch after lurch and yanks, rolls and slides nearly continually. Optimus started to suspect after half a joor of the excuse for driving that Megatron was playing it up and seeking out every bump and pothole on the road deliberately while jerking the wheel completely random to make him even more miserable. He certainly had no affinity for the gearshift and hefted it like it was a weapon's shaft. Optimus warned him once what would happen if he broke it and Megatron certainly skirted that point a couple of times since. It had to be deliberate. The warlord would harm himself gladly if it meant a jab at Optimus and really, how can somemech be unable to drive to this degree?!

"How should I have known that? Every mech I knew had alt modesSSS!"

He hardly finished the sentence when another sudden screetch sounded from underneath and Optimus was launched into the air, flew blindly a little inside the cabin before momentum made him crash into his own windshield. He felt rather than heard two relatively small cracks keenly – one was the gun's safety which was like a strong pinch on his frame, a cruel pinch of a metrotitan; while the other was the clear steelglass now sporting a nice spiderweb of cracks. An expletive was in his vocalizer, ready to shout out by comms as they were conversing so far, when a louder snap cut his thoughts in half and made the truck lurch violently again.

"For Primus's sake! How many wheels do you intend to blow yet?"

"You have far too many, Prime!"

Megatron sneered back, appearing blithely unconcerned by the rapidly amortizing frame he was residing in. It was clear from the beginning that for some reason the warlord was particularly offended by the tires. Maybe it was his automatic 'roll out' when they started? Optimus hoped not. It was just a rote sentence he recited almost automatically these orns. His magazin ached from the whack it got from the impact and the place of the broken off piece – such a tiny thing, but so important – stung far more than Optimus expected from such a little part.

"I'll have you know that at the next bump I'll shoot."

"Empty threats, Autobot, empty threats."

"No, really. You just broke my safety. Your safety."

Optimus was too tired and battered even to laugh at the sudden silence that greeted his announcement. The violently surging truck slowed down a tiny bit and it's eccentric course on the tarmac evened out slightly. Just in time, Optimus thought, he had counted five burst tires and was very concerned by the sound of the third axle. Not to mention the gearshift, the suspension and… slag you, Megatron, nearly everything. He got that one hit back with generous interest.

"Worried, Megatron?"

"I know my specs." – came the surprisingly calm answer from around him – "If I… I mean **you** shoot inside you… I mean **me** , we'd probably both be deactivated."

"Does that mean that you'll now drive more carefully?" – Optimus enquired acidly from his position under the pedals where the last surge wedged him. The announcement froze his insides a little bit because it sounded honest. Too honest. He was suddenly glad of his stuck state that prevented further tossing in the cabin, even though the gun's sight now stared permanently at a dead bug somehow sharing the space with him, showing it in great detail. The sight was incredibly precise and the bug was mere inches from it. Optimus idly wondered about the species. Megatron's voice echoed cheerfully around him. It was a so patently false cheer Optimus didn't even bother to mention it.

"Hey, I think I'm getting the hang of it finally. Still too many wheels though – how can you control them all?"

Optimus counted the first one hundred digits of the pi before answering. He still had a tactical display and it was swamped with purple at every bump and lurch. He needed every trick to stay calm, especially now with the broken safety. Though as the time went on he more and more considered ending the war for good even if it included his own sacrifice.

"You don't have to control them all one by one, you know? It works without blowing them all too."

"You don't control your own frame?"- the sneer was back in his voice.

They were almost driving in a straight line now. Optimus got several comms from his Autobots enquiring what Megatron was doing now and put them to rest quickly.

"Well, let me put it this way: How do you control that subroutine so you don't shoot Starscream all the time? It's very annoying."

The laughter echoed again and Megatron made small corrections with the wheel. He still wasn't as smooth as Optimus would have liked, but at least he was staying on the road now. Even the laughter sounded less forced now.

"Well, it takes practice. I mean to know when to actually shoot the brat."

Optimus lifted a brow-ridge mentally. He saw nothing – the dead bug didn't count - and sensed nothing and to dispel the slightly claustrophobic feeling of where he was – quite literally under Megatron's pedes-pedals – he kept talking.

"I wouldn't know. Never tried to shoot Prowl."

"He probably doesn't try to depose you every decaorn."

"Why would he?"

Optimus felt the raised brow plates in the sudden silence of the cab. Well, silence being relative over his straining engine.

"Why wouldn't he? It's the way of advancement. It is expected, just like it is expected of me to put Starscream back to his place when he tries."

For the life of him, Optimus just couldn't understand how such a system worked. How could they trust each other? Ohhh, right, they didn't. Even now, driving among the Autobots' vehicle modes, Optimus felt that part of Megatron's field – and some sensors – were directed upwards, where he supposed the Seeker was flying above them and laughing himself to an early deactivation. It was clear that the tyrant's tactical assessment still considered the Seeker as the biggest threat – the Autobots wouldn't harm him in Optimus's frame, but for Starscream it must have looked as a golden opportunity to get rid of him, enough so that he, too dared the Autobots' company alone.

"It just… I suppose it seems wasteful for me."

"It brings out the best from him – and if I take his suggestions, I don't have to credit him."

Megatron sounded almost calm by this time and Optimus was inordinately glad for it. Partly it meant a much smoother ride, but also it gave him a rare insight into the Decepticons' mindset and inner workings. The callousness though… it galled him.

"Why not give him that? Wouldn't he be a little… less treacherous then?"

"Who cares?"

"One orn he will succeed, you know?"

They were slowing down. Primus, Optimus hoped that they were nearing the Ark finally. It would still be a chaos to get back both of them into their proper frames, but he didn't think he could take much more of the ride. Megatron turned down from the asphalt road and into the gravelly one leading to the Autobot ship. He grumbled about the rocks hitting his undercarriage, the first real sign that he, too hated the drive as much as Optimus suspected him to.

"Not while I live!"

For a nanoklik they were both silent, but as Megatron stopped, the ridiculousness of the sentence suddenly became obvious to them and they started to laugh, a totally surprisingly friendly and companionable laugh… The cabin shook around Optimus and when he heard the horn going off he felt the Autobots transform and stand around them suspiciously. The shaking got worse and Optimus felt like…

"Hey…!"

… transformation sounding all around him and he was airborne once again, slightly panicking as he remembered the lack of safety, before he dropping down and hitting something hard… and still inside his cab so he didn't dare to transform back to a more manageable frame.

 _What the frag?_

His narrow tunnel vision of the gun's sight showed him the spiderweb cracks on his windshield… from the inside – and the Ark's mountain through it, his Autobots standing around… and Optimus realized what happened.

"Megatron! Let me out of you this instant!"

"Huhh?"

One of the windshields swung open and Optimus was inelegantly yanked out. The dizziness of the sudden motion was very annoying, just like the nonchalance with which Megatron swung him around. Optimus had had enough of being handled. He shook all over and initiated the transformation sequence not even waiting for Megatron to let go of him. The change was just as disorientating as the first time. Optimus dropped onto his still too heavy pedes, grunted as the weight settled about him and glared at Megatron. For this he was glad for the red optics, they made a much more satisfying angry glare than his own blue set. The height difference, slight as it was, also helped. Megatron took a step backwards.

"Hey, it's not like I ever take on passengers!"

"You did it deliberately!"

"I did not!"

"Just like the driving!"

"I deny any pointless accusations!"

"You blew five tires! FIVE!"

Optimus knew he was shouting and that he should stop. But he couldn't help himself, the long and bumpy ride home, the damage to his frame he kept listing in his processor, and the annoying insistence of the purple-swathed tactical display eroded his patience. Megatron of course needed nothing to answer in kind and fuel Optimus's fury even further...

"They were obviously inferior!"

"I never blew a tire in my function!"

"Well I never broke my safety before either!"

"That's your fault as well!"

They strained towards the other, red and blue optics flaring in angry indignation and shouted at each other – until a hilarious cackle broke into their heated little circle. Starscream was obviously having the time of his life watching them make a fool of themselves. It ashamed Optimus – and obviously Megatron too, because he saw his frame take a threatening step towards the Seeker, right arm raised in a way very familiar by now to the Autobot leader…

"And just what do you intend, Mighty Megatron? You seem to miss the means for it!"

"Shut up, Starscream!"

Optimus glanced at the fusion cannon, suddenly glad that he now possessed it. Though the tactical display was still flashing at him its maniac suggestions, it did become easier with time to deny its mad requests. It was obvious that Megatron had far less inclination to do so.

"And how will you make me… My Lord?"

But true, the Seeker was far more obnoxious than even his tolerance. Optimus caught Prowl's displeased glance too and Jazz was more fidgety than usual as well. And they were still just outside the Ark, the research into the frame-exchange hasn't even started… how long were they stuck in each other's bodies still? How long they had to endure the blunders, the jokes, the verbal taunts from Starscream, the disdain from Megatron, the silent but perceivable displease from the Autobots?

Optimus whirled and stalked into the Ark's doorway, trying in vain to control his own displeased scowl. He paid no processor to how it must have looked on Megatron's visage.

It was a mistake to forget about Red Alert.


	3. Chapter 3

_Note:The third and last chapter is ready and though it is much less humorous than the previous one, I guess I have mined out all good jokes from the body swap already and it left only to conclude the story - such as it is. :-)_

 _Umm, and yeah, I completely invented the science-part and hope that noone tries to make any sense of it. :-)_

* * *

Optimus looked ready to use Megatron's cannon by the time they arrived to the Ark's entrance. On whom, Jazz wasn't sure, but the business end of the cannon continually smoldered with purple fire and he wasn't sure if Op was aware of that worrying little fact… and just how much he was in control of that fearsome weapon. That little spat with Megatron was totally uncharacteristic of the Prime, who usually possessed vast amounts of patience, even when dealing with the tyrant. He wasn't the only one who noticed the cannon either – as Optimus kept moving around most Autobots subtly shifted out of its line of fire, while trying to look nonchalant. Most of them kept clear of Megatron too, which resulted a strange, queer, almost dance-like swirling in the group. Jazz nearly snickered out loud when he caught Sunstreaker switching his glower between the two, hard-coded instincts and current appearances conflicting in the warrior's processor.

But they seemed to control their urges to actually fight with each other so far, so Jazz tentatively hoped that they could manage the exchange back with minimal casualties. Ohh, he did notice Megatron trying to unsubtly amortize Optimus's frame, but the tyrant slyly claimed his inability and unwillingness to drive 'such inferior vehicles' as he put it. Optimus was in a distinct disadvantage with the gun alt, though it made the saboteur think of several ideas they could use in future battles. An enemy commander who couldn't see, speak or move while in gun mode? Jazz made a note of speak with Wheeljack about it. After of course the inventor reversed whatever effect he made to exchange their leaders' frames, for Jazz there was not even a shred of doubt as to who caused it. It was always Wheeljack – and he was uncharacteristically subdued on the way back, nearly hiding from Optimus's attention.

Jazz hoped that that silence was a sign of their erratic inventor was already thinking on reversing the effect – and not a new invention. Wheeljack, as most inventors, was often hard to point in the right direction… ooops… Jazz shook his helm and hurried to catch up with the others. While he was thinking, Optimus – in his new, silvery frame that fitted him like a lace glove would to a Seeker's taloned servo - was already at the entrance and disappearing into it with a scowl entirely too much befitting for the enemy warlord… and Jazz had a sudden, bad foreboding.

"Has anyone told it to Red?"

He knew that Prowl was fighting with glitching all the way back at the improbable scenario and Megatron's erratic behaviour on the road. Jazz himself was watching Starscream to do anything suspicious but the blasted Seeker was busy laughing off his tailfins and if he planned anything he gave no visible sign of it. He knew that Ironhide was not taking off his optics off of the pair of leaders either and briefing Red Alert was definitely not the frontliners' task. That left… nomech?

They all came to the same conclusion at once and suddenly every Autobot broke into a run at the suddenly erupting sounds of loud, angry shouting and flashes of weapons' discharge from inside. On his way Jazz briefly noted the strange, cruelly amused smirk on Optimus's faceplates, now devoid of the mask and noted Starscream too who looked to seriously consider rolling on the floor laughing. Sunstreaker, who had been the closest to the Ark, disappeared into the entrance and the sounds of fighting, if anything increased. Jazz cursed and ran faster, arriving into the entrance corridor just after Prowl.

Inside it was a disaster in the making. The speakers blared the highest alert and Red Alert's panicky voice, the strobing red-purple lights painted the corridor vividly in nightmarish colours and vied with the brighter flashes of shots from a horde of security drones – and Optimus apparently lost the battle of wills with Megatron's cannon, because there were blackened-melted sections on the walls and at least two security drones lay crumpled on the floor. Sunstreaker, and Jazz gave the frontliner plenty of points for it, was trying to scream to Red Alert to call back the drones while he covered Optimus from their shots. Unfortunately the overwhelmed security director wasn't inclined to listen to the frontliner over the facts he saw with his own optics.

Jazz hurriedly commed to Red to explain the situation but he was cut off with a screech of frequencies. By the look of extreme frustration on Prowl's face, he too was ignored by Red Alert, who must have fallen off straight into the deep end of his everpresent paranoia. They were in deep slag if Red decided that they were traitors working with Megatron and present appearances unfortunately supported this idea. Jazz took cover at the entrance as the drones shot at every mech approaching and tried to think fast. His attention was suddenly pulled back outside where Megatron stood nearby with his arms crossed and Optimus's deep voice sounding strangely smug…

"They might end the war for us, Starscream."

Jazz didn't hear the answer of the Seeker amidst his high-pitched cackles, but he caught the amused answer from Megatron.

"The frame is little price to watch the Autobots destroy each other."

And he couldn't even blame the opportunistic slaggers for the situation. _Frag_! They caused this mess themselves, first Wheeljack, then by not preventing Red Alert's… _meltdown_. Jazz tried to work out a solution fast but it seemed hopelessly complicated and with Red Alert's paranoia being what it was he couldn't hope to convince him that Megatron was Optimus and none of them turned traitor or got mad all of a sudden. Especially as he was not even listening to them.

But as he fretted there, suddenly the sounds of the battle ceased. Jazz sneaked a look around the corner hoping to Primus not to find grey frames on the floor. The drones stood down, the flashing alert stopped and Red's panicky voice no longer blared from the loudspeakers amidst the billowing smoke. Optimus and Sunstreaker were also peering out from behind their section of the wall and their gold-silver pair looked so strange for a klik Jazz nearly glitched himself. Then he saw Ratchet casually strolling in the entrance at ease and casual as you please and the saboteur blinked several times. Nope. One nonchalant medic, check. Improbable silence and calm, check. He distinctly felt behind the events, not understanding how it happened. Staring at Ratchet, the CMO apparently understood his unspoken question.

"What? You didn't think I don't have the means to declare him medically unfit and lock him out of Teletraan?"

Jazz opened his lipplates but nothing came out. He should have known about this! He was the Spec Ops Commander and Ratchet just a CMO!

"Good thinking, Ratchet." Optimus straightened up, pulling Sunstreaker with him, which made the golden frontliner flinch before accepting the help from the black servos. "Now let's sort it out before he convinces Teletraan that we are the bad guys."

"And let's get him to medbay before he completely melts down." – Ratchet grumbled as they moved inside.

"I will take command if you accompany our… guests." – Prowl gladly entrusted the Decepticons to Jazz.

Jazz, fighting off his shock turned back to see their guests… visitors. Megatron appeared unfazed but the saboteur thought he saw a flash of disappointment in Optimus's optics and Starscream – at least and at last! – stopped laughing.

"Well, come on in." – he tried to play it cool – "Straight into Wheeljack's lab, don't stop to shoot anymech and let's find out what happened. 'Jack?"

"I'm here. Thought I'd wait out the skirmish."

They went deeper into the Ark, to the unoccupied part where the inventor's oft-exploding lab was situated. Jazz was a bit satisfied to see the nervous twitching of Starscream's wings. He had wanted to come now, hadn't he?

"So… spill it. What was that, Jack?"

Wheeljack cast a nervous glance at Megatron, another one to Optimus and his usual cheer was suspiciously not present. He wrung his servos together before pointing at a blackened contraption on the table he just set down.

"umm… that… was… it."

Jazz felt a processor-ache winging its way to him and inexorably settling in.

"It… broke?"

Optimus frowned and Megatron scowled. Or vice versa, the saboteur had little interest in telling which of them did what. Starscream lifted a brow plate and his long talons started to poke the blackened… something on the table, murmuring something vaguely scientific-sounding under his vent.

"NO!"

"Don't touch it!"

"Leave it alone, Seeker!"

Starscream looked back unrepentantly at them and the shadow of a smirk looked almost… threatening.

"Can't make it any worse now, can I?" – Jazz looked at him horrified. Did he have to invoke the curse of Murphy? – "Besides it looks as though… you tried to laterally transduct the gamma-channel output with the prion emitter's phase-resistor and splice them together, have you?"

They all stared at him mute. Even Megatron looked dumbfounded, which appeared pretty strange on Optimus's face. The Seeker appeared not to notice their shock – or he was just too smug to show it. He nudged a particular part and it gave out some feeble sparks – and gave them all spark palpitations until they saw the sparks die out quickly and cause nothing more than a charred smell in the lab.

"To loosen the bonds among Cybertronium atoms and make us dissolve inside out? Pretty ingenious."

Starscream stopped poking the contraption and looked up, smirk back in place firmly, though his optics remained cold and hard. He seemingly ignored the reaction his actions and words caused.

"And pretty ruthless from an Autobot too. Never thought of switching sides?"

Jazz understood only every second word or so, but they still sounded bad. His glance at Wheeljack included a stern disapproval, though it was nothing in weight compared to Optimus's ' _I'm so disappointed in you_ ' look. And just how the Prime managed _that look_ with Megatron's sinister optics, Jazz couldn't fathom…

"No… No! I just tried to separate the prions and make them …"

Jazz tuned out the rest which he wouldn't understand anyhow. Wheeljack's explanation went on for a couple of breems and only Starscream's optics were not glazed by the end of it. But he had only one concern anyhow and it wasn't understanding the mad science behind the mess…

"Can you reverse the effects?"

"Easy." – Starscream's digits were back into the tangle of wires and parts – "Just switch this so the channel it emits is not gamma, but delta and… "

Wheeljack nodded enthusiastically, optics widening before regaining their usual, slightly maniac flash.

"Yes, yes it would work! How did you know…?"

Starscream's faceplate was a study in snobbish superiority and haughty disdain and his wings flared high and wide. Jazz patted one away from his faceplates. The lab suddenly appeared to be too small for the Seeker's ego and his wings adequately conveyed that attitude.

"You Autobots are not the only ones into weapons research. I discarded this idea for its sheer stupidity vorns ago."

Megatron snorted, which was so far the strangest sound Jazz has ever heard from Optimus's vocalizer and the Seeker's left wing twitched.

"Discarded, ehh? Wasn't it by any chance the reason behind Thundercracker's pranking spree and Skywarp adopting an organic dog a vorn or so ago?"

Starscream hissed angrily and stomped… actually stomped like a human adolescent in a temper tantrum. Wheeljack snickered and Jazz joined him. It was a welcome change to laugh at the Decepticons for awhile. Megatron's red optics were comically wide and even the fusion cannon stopped smoldering its purple fire. The real Megatron was smirking nastily at his Second, who sputtered out his answer with wings comically flapping behind him.

"At least I didn't bring an untried contraption to the battlefield!"

"What about Ravage attempting to fly and Laserbeak walking on wings?"

Starscream's sputter arched up into screeching and all mechs present, regardless of faction flinched. Hard.

"They sneaked into my lab! It was their fault!"

"They why did you avoid Soundwave for a vorn afterwards?"

Starscream grumbled something about overprotective tape-recorders and their obnoxious cassettes but his wings drooped low and he looked around nervously. Jazz noticed Wheeljack's shoulders shake with silent laughter as the inventor worked on the… weapon? Jazz wasn't even sure what it was, but the blackened mess of wires and parts started to change into something workable again.

"Not there!"

The inventor glanced at the Seeker before soldering a wire to a particular part. Starscream actually looked nervous and his voice was even higher than before.

"Why?"

"That causes… I mean that should cause… slag, it's worse than simply swapping frames."

Jazz lifted not one but both brow plates. The jet sounded downright frightened and ready to bolt if the angle of his wings were any indication.

"What? Or should I not ask?"

"Pit, no! Connect it there and finish this slag!"

Wheeljack nodded agreeably enough, but Jazz almost saw the wheels turn in his helm. He swore to destroy the thing the nanoklik their leaders were safely back in their proper frames and before Wheeljack could try the setting that made the Seeker so nervous.

"Ready!" – the inventor's announcement came surprisingly fast.

"So… what do we do?" – Optimus enquired.

"Just stand close to each other… and everymech else come over to this side."

Jazz scooted to Wheeljack's left side, but kept well clear of the device too. Starscream did the same, and though the slight smirk in the Seeker's face was worrying, Jazz didn't have time to find out what he plotted before…

… the device gave off a screech to put the Screamer to shame and spat out more sparks than Jazz felt comfortable with.

"Wha…?"

"No, no, it's okay…"

Wheeljack turned a dial and the sparks stopped. Instead an optic-searing bright light-beam shot out and engulfed the whole corner of the lab where Optimus and Megatron stood uneasily beside each other. It went on for a klik before the light shut off and another while they blinked the stars out of their vision.

Optimus cast a querulous glance to Megatron and got a scowl back for an answer, the expression suddenly fitting for their faces. Jazz sighed in relief. Starscream grimaced with disappointment. Ratchet's comm caught them all by surprise.

"They had best be back to normal, because Red is glitching again."

"They are, docbot, they are. And the Decepticons are leaving now. Right?"

Optimus nodded and they ushered out their visitors. It was an uneasy silence on the way out, though Jazz could see that Op was feeling glad to be back to his frame and Megatron touched his cannon from time to time, like making sure it was there again.

"Well. Wasn't that fun?"

Judging by Optimus's and Megatron's faces Starscream's mock-innocent question and barely hidden mirth was going to be met with violence, Jazz concluded. From both sides. But he had somewhere to be, ummm, like checking on Wheeljack to destroy the device.

Starscream was on his own in this.


End file.
